Distinguishing features: Test is biserial throughout, with variable asymmetry as seen in edge view. Earlier species display twisted tests and symmetrical periapertural structures; evolved ones show symmetrical tests in edge view and asymmetrical periapertural structures. When compared with the second chamber, the size of the proloculus is variable and generally larger, but in some rarer specimens it is smaller. Chamber shape is globular to reniform. Sutures are distinct, depressed, straight, and oblique to the test axis of growth. Test periphery is rounded. Aperture is low to medium high arch at the base of the last formed chamber and bordered by asymmetrical periapertural structures. Periapertural structures of the primitive species consist of asubangular ridge on one side and a rim on the opposite side; two asymmetrical flanges border the aperture in the evolvedspecies. A small relict toothplate can be occasionally present. Chamber surface is smooth. Test wall is calcitic, hyaline, nannoperforate to microperforate.

Geological Range: Last occurrence (top): within Turonian Stage (89.77-93.90Ma, top in Turonian stage). Data source: Total of range of species in this databaseFirst occurrence (base): within Albian Stage (100.50-112.95Ma, base in Albian stage). Data source: Total of range of species in this database

Plot of occurrence data:

Dec 2017 - Plotting of Neptune data has been re-enabled on the Mesozoic pages following revision of the age-models in Neptune. The data is, however, still very sparse for the Early Cretaceous